Irreversible actuators of personal protection devices for passive safety systems in vehicles, such as pyrotechnic safety belts and airbags, are today generally triggered on the basis of a contact sensor system. Reversible actuators of personal protection devices, such as electromotoric safety belts, are today triggered already in a pre-crash phase, on the basis of an environmental sensor system such as radar, video, or amalgamated systems. The triggering of the irreversible actuators requires a very high degree of robustness. This is a result of the high safety demands regarding “false triggerings” (false positives) based on the assessment of risk, and of the very low degree of acceptance of false positives, because even apart from the safety risk, false positives require repair, which is costly and exasperating.
A timely recognition of an unavoidable collision required for the irreversible triggering of pyrotechnic actuators in the pre-trigger region of approximately 80 to 40 ms before impact can be realized for many crash situations using today's environmental sensor systems. The basis for this is provided by conventional pre-crash functions and automatic emergency braking functions.
However, these conventional systems are for example designed such that adequate validation performance for avoiding false interventions or false positives requires a standard of less than one time over the life of the vehicle. For pre-trigger functions, a much higher robustness requirement against false positives is indicated, which is at least three orders of magnitude below the current degree of validation for false interventions or false positives.
In conventional so-called black box validation, driving in the field takes place with a prototype system for so many hours that the corresponding degree of robustness can be reliably set when no false positive has occurred in this time span. If the required robustness is for example less than 10−5 errors/operating hour, then driving takes place in the field with the prototype system for 105 operating hours. For mass production, this cannot be done for the required order of magnitude of the pre-triggering function.